Add proxy for horizon with cookie support

This patch adds a proxy for load-balancing horizon. Persistence is
done with a SERVERID cookie. This patch also extends the proxy defined
resource to accept more options (addr, mode, listen_options,
member_options, and define_cookies).
Remove proxy for swift

Since we're not currently deploying swift via quickstack, comment out
the code the creates a load-balancer proxy for swift.
Merge pull request #28 from rohara/master

Add proxy for horizon with cookie support